msm: vidc: Disable DCVS when Turbo mode is enabled

When clients enabled Turbo mode, it is expected that Venus runs
at Turbo frequency. But due to DCVS it may go to Nominal which is
different from clients expectation. Hence disable DCVS when Turbo
mode is enabled.

Change-Id: Ia95b55cdc93af599e7cb1930b72ba9bd60b23a96
Signed-off-by: Praneeth Paladugu <ppaladug@codeaurora.org>
Signed-off-by: Sowmya Pandiri <spandiri@codeaurora.org>